1. Field of the Invention
The present invention relates to nozzles assemblies and more specifically to nozzle assemblies which enable quick and easy connection/disconnection in cramped and hazardous environments such as encountered in nuclear reactors.
2. Description of the Prior Art
It is essential that a hermetic radiation proof seal be maintained between the interior and exterior of a pressure vessel such as a nuclear reactor. It is also necessary to monitor the operations of a reactor using In-Core-Instruments (ICI). However, this latter requirement necessitates the provision of nozzles through which the instruments can be sealingly introduced into the core. Examples of such an arrangements are shown in U.S. Pat. No. 4,723,795 issued on Feb. 9, 1988 in the name of Shenoy and U.S. Pat. No. 4,655,483 issued on Apr. 7, 1987 in the name of Margotta. The documents discloses techniques for providing fluid tight connections between a nozzle and a column which is concentrically supported within the nozzle.
FIG. 1 shows a less preferred embodiment of the type of nozzle to which the present invention pertains. This arrangement is such as to provide a fluid tight radioactive proof seal for a plurality of ICI (In Core Instruments) and allows the operative connection with external controls and monitoring arrangements.
This arrangement features the use of a Grayloc hub 10 which is clamped securely to a Grayloc flange 12 formed at the upper end of an ICI nozzle 14. However, with this arrangement when it is required to disassemble the same, the Grayloc clamp 16 is unbolted and each individual ICI nut 18 is then removed and the individual ICI's are then clustered together under a bullet nose. The above-mentioned Graylock hub and Graylock clamp are products of the Gray Tool Company, Houston, Tex.
However, this induces the drawback that the disassembly process is both strenuous and time consuming. It is also carried out in very cramped conditions and in a radioactive environment. Accordingly, the operators are required to wear protective suiting and must be careful to watch the amount of time for which they are exposed to the radiation.
Accordingly, there is a need for an arrangement which can reduce both the effort and time required to achieve the disassembly of an ICI nozzle which is carried out each time a refueling or instrument change is required, in order to reduce the reactor down time and more importantly to reduce the health risks associated with working the above mentioned hazardous environment.